Question 1:
###Which of the following terms correctly characterize(s) the Internet?
Correct answers
- Heterogeneous network
- Virtual network
Wrong answers
- Closed network
- Centrally administered network
Explanation
The Internet is an amalgamation of many different networks which are interconnected. The architecture of those different physical networks may differ. Every day, more and more networks are connected to the Internet and make it grow even bigger. So the Internet is not a closed network. As it consists of many networks, there is no global or central administration.
Question 2:
Which answer correctly characterizes a property of the hardware layer?
Correct answer
- Bit stream transmission on the cable
Explanation
The hardware layer, sometimes not considered a layer of the TCP/IP stack, is the bottom layer of the model. Here it is ensured that "messages" are send as an analog representation. Depending on the network architecture, this could be electricity on a copper cable.
Question 3:
Which answer correctly characterizes a property of the link layer?
Correct answer
- Data packet formats and local network addressing
Explanation
Components in the link layer make sure that there is a way of addressing in local networks so that data packets, whose format is also defined by the link layer, can be addressed and sent in this network.
Question 4:
Which answer correctly characterizes a property of the Internet layer?
Correct answer
- Logical addressing and routing
Explanation
The Internet layer is the layer where we can also find the Internet protocol (IP, IPv6). Here, we can work with logical addresses (IP address) of computers that can be in another (interconnected) network. Besides addressing, also routing is given so that packets can be sent via many intermediate systems without the necessity of specifying the route before sending a data packet.
Question 5:
Which answer correctly characterizes a property of the transport layer?
Correct answer
- Data transmission integrity
Explanation
TCP, as the most-known protocol of the transport layer, is responsible for taking care that data packets reach the receipient. In case a packet gets lost on the way, there will be a retransmission of the missing packet/segment. So TCP ensures that all data sent will sooner or later arrive at the recipient's.
Question 6:
Which answer correctly characterizes a property of the application layer?
Correct answer
- Interface between programs and networks
Explanation
The application layer with protocols such as HTTP, SMTP, IMAP, FTP, and many more, acts as an interface for software programs that are located on top of the TCP/IP stack.
Question 7:
If you required every peer to be able to communicate with every other peer at any time (also simultaneously!), which network switching approach requires fewer network cables?
Correct answer
- Packet switching
Explanation
With packet switching, it is not necessary, that there is an exclusively reserved connection between every pair of stations. So it is enough if somehow all of the 6 peers are connected to one another. So 5 connections are sufficient if the network is built like A--B--C--D--E--F.
Question 8:
In a circuit-switched network, 6 peers should be able to communicate with each other at all times. How many lines are required to accomplish this requirement?
Correct answer
- 15
Explanation
In a circuit-switched network, for every two peers, there has to be an exclusive connection. So if we have 6 peers named A, B, C, D, E, F, we can count the numbers of connections easily: A needs 5 connections to be able to communicate with the other 5 peers. For B, we need 4 more connections (because we already counted the connection between A and B). For C: +3, for D +2, for E +1 connection. So, we need 15 connections in total.
Question 9:
Packet Switching
Network topology
Given the network above, Host A fetches 10 MB from the Web server. The maximum packet size should be 2592 bytes, a packet header has the size of 32 bytes. Give the duration of the transmission.
Hint: Please calculate as precise as possible (use a calculator!) and just round on the end.
Correct answer
- 4.052 seconds
Question 10:
Which layer does the protocol "IPv4" belong to?
Correct answer
- Internet layer
Explanation
The name already gives it away... the Internet protocol version 4 belongs to the Interet layer.
Question 11:
Which layer does the protocol "TCP" belong to?
Correct answer
- Transport layer
Explanation
TCP is the best-known protocol of the transport layer. Another one would be UDP.
Question 12:
Which layer does the protocol "Ethernet" belong to?
Correct answer
- Link layer
Explanation
Ethernet, as used in many local area networks (LAN), is a protocol of the link layer.
Question 13:
Which layer does the protocol "DNS" belong to?
Correct answer
- Application layer
Explanation
DNS, the Domain Name System, is prominent for translating domain names to numerical IP adresses. It is located in the application layer.